A/N: Okay, so it's time for yet another Chuck/Blair lighthearted, fluff piece. This one was inspired by my own pathetic life when I was driving to campus, on a Saturday, to work on my microbiology project, and began imagining what it would be like if the really adorable guy in my class were working on his project at the same time I was and we were the only two in the classroom. My dirty mind came up with a little different scenario than the one I wrote out for our fav Gossip Girl couple, but I wanted to keep it clean. haha. Anyway, enough about my non-existant love-life and on with the fic! I hope you all enjoy!

Disclaimer: So, last time I checked, I didn't own Gossip Girl. Hang on...I'm gonna check again. Maybe it's changed. Oh, no, wait. Still don't own it. Damn. I was hoping I would get to be rich.

"Beneath our walls is chemistry" ~Teddy Geiger, Chemistry

One of the most basic laws of chemistry is the Law of Conservation of Mass: matter can neither be created nor destroyed, though it can be rearranged. And seeing as how Blair Waldorf was a smart girl, she was aware of this law and knew she could not literally destroy Chuck Bass, but she could always just rearrange his face a little.

This was the thought running through Blair's mind as she sat in the backseat of her limo, fuming. She was on her way to school, on a Saturday, mind you, and to say the least, she wasn't exactly pleased.

It was bad enough that her chemistry teacher at Constance Billiard assigned a joint project with the boys from St. Jude's. It got a little worse when she found out, by the sheer annoying concept of "alternating alphabetical order" where the boy with the first last name gets paired up with the girl with the last last name and so on, her partner was going to be none other than Charles Bartholomew Bass himself. Those things were bad, true, but Blair's breaking point came when yesterday, when everyone was supposed to get together to do their project, Chuck was nowhere to be found. And when she asked Serena about it, she informed her that her step-brother was still at home, sleeping off yet another hangover. And you do want to know that worst part? The part that made Blair's blood boil? He was not sleeping it off alone.

Not that Blair cared. She could care less if he wanted to waste his time with skinny, blonde whores who are only looking for a night with the rich, infamous playboy, Chuck Bass. All the power to him. But what she did care about was that she now had to drag herself out of bed early on a Saturday morning and give up a day of shopping with Serena to spend it in a classroom and come out, she was sure, smelling like all sorts of noxious chemicals.

She had asked her teacher if she could just do the experiment herself, after all, she was perfectly capable of working on her own. In fact, she preferred it that way. There was less of a chance of someone screwing her over by misreading directions, adding the wrong chemicals, or you know, screwing other girls and not showing up. But anyway, her request was denied by the teacher, claiming, "It would do her good to work on teambuilding skills." Whatever. In any event, that's how Blair found herself at school on a Saturday, sitting in the chemistry lab, waiting for her partner to arrive.

After looking at the clock on the wall for what seemed like the thousandth time since she arrived, Blair let out an exasperated sigh. Chuck was fifteen minutes late and counting. She knew she shouldn't have been surprised. When Chuck is the last person she wants to see, he shows up everywhere. However, the one time she was expecting him, he was nowhere to be found.

Ten minutes later, Blair had had enough. She had gathered all the necessary materials for the experiment and was now sitting at a lab bench, twiddling her thumbs. Fishing her cell phone out of her purse, she flipped it open and began composing a text message to her long overdue partner.

However, when she halfway done typing her expletive filled message, the intended recipient of said message came sauntering through the lab door with a grin on his face, as if everything was just peachy.

"Honey, I'm home," he declared smugly, opening his arms as if he were waiting for a hug.

Blair snapped her cell shut angrily. "It's about time you showed up, Bass," she said, her brown eyes shooting daggers at him.

"Take it easy, would you?" Chuck said, shrugging his book bag off his shoulder and leaving it a heap on the floor. "I'm not that late," he said, taking a seat on the stool next to Blair.

Her eyebrows shot up. "Oh really?" she asked with a short, incredulous laugh. "You think so? Because by my watch," she said, looking pointedly at her expensive Cartier watch, "you are approximately…24 hours late, give or take a few minutes."

Chuck rolled his eyes. "Well, excuse me for being sick yesterday."

"Sick!? Ha!" Blair exclaimed. "Hung-over does not count as sick, Bass."

He looked at her through narrowed eyes. "You talked to Serena," he stated.

She looked at him doubtfully. "You thought I wouldn't?" she asked, an amused tone in her voice.

"No, I assumed you would," he said coolly. "But it does seem like I'll have to have a little chat with her about brother-sister confidentiality."

"Which, of course, is nullified by the best friend's tell each other everything, especially when it comes to sketchy, nonexistent chemistry partners agreement."

Chuck smirked. "Siblings trump friends," he said like it should have been obvious.

"Okay, one:" Blair said, holding out one finger. "I cannot believe you just actually used the word 'trump' and two:" she said, bringing up another finger. "you're step-siblings. Totally doesn't count."

"On the contrary-"

Blair held up a hand, silencing him. "You know what? It doesn't even matter. Can we just do this?" she asked, pulling her lab sheets out of her binder. "The sooner we get this done, the sooner I get out of here and away from you and the sooner you can get back to your whores."

Chuck snorted. "I'm glad you think so highly of me, Waldorf."

"Were you or were you not with some little gold-digging skank Thursday night which resulted in us being at school on a Saturday?" she asked confidently.

He shook his head. "I really am going to have to have that chat with Serena."

"Fine. Whatever," Blair said, rolling her eyes. "But you just make yourself useful and go weigh out three grams of the salicylic acid?" she said, motioning to the group of chemicals she had gathered while she was waiting for Chuck.

He eyed the pile and then looked back at her, a tiny smile playing on his lips. "You seem to be assuming that I know what the hell that actually is," he said with a small laugh.

"It's the clear crystals in the bottle marked 'salicylic acid'."

Chuck thought about it for a moment. "Hmm," he said, stroking his chin as if he were deep in thought. "Makes sense," he decided, grabbing the bottle and sauntering over to the scale.

Blair grabbed a bottle of acetic anhydride and began carefully pouring it into a graduated cylinder. Chuck came back and placed the salicylic acid in front of her. "So what exactly are we doing with this salcyclic acid, anyway?" he asked, sliding back onto the stool.

"Salicylic," she corrected with a sigh. "And I'm synthesizing acetylsalicylic acid. You are going to hand me things and not get in the way," she said as her poured both the salicylic acid and acetic anhydride into an Erlenmeyer flask.

"English, please, Waldorf."

His blatant ignorance warranted an eye roll from her. "Acetylsalicylic acid. Common name, aspirin," she informed him, using a voice that is usually reserved for a teacher talking to her kindergarteners. "Don't you pay any attention in class?"

"No," he said automatically, obviously unashamed.

Blair scoffed. "Of course not. But in any case, this may actually be a useful experiment seeing as how you could use some aspirin for that hangover of yours, and I could use some because I already know that being here with you is going to give me a major headache."

Chuck scooted his stool closer to hers. Leaning close to her, he whispered in her ear, "If you want to come up to my suite after this, I'll give you a major-"

She whirled her head around so she could see him face-to-face, cutting him off. "Finish that sentence and I swear to you, you will get this phosphoric acid down your pants," she said harshly, causing Chuck's mouth to close immediately. "Not that you shouldn't be used to a burning sensation down there," she added under her breath, turning her attention back to the flask in front of her.

"What exactly are you implying?" he asked, not actually offended.

Blair simply shrugged and added a few drops of phosphoric acid to the mixture in the flask instead of down Chuck's pants.

"I take care of my business, thank you very much."

"Whatever you say," she said, pushing the flask off to the side.

"Are we done?" Chuck asked.

She eyed him critically. "Does that look like aspirin to you?" she asked. If it wasn't clear that she doubted his intelligence earlier, the sarcasm oozing out of her voice now made it blatantly obvious.

At least Chuck was intelligence enough to catch the sardonic tone of Blair's voice. "Enough with the sarcasm," he said, rather sharply. "It's a valid question considering you won't clue me in as to what you're doing."

Blair fought the urge to spout off another smart-alecky remark and instead calmly explained, "We have to wait a few minutes to allow the reaction to occur. Not all chemical reactions are instantaneous."

"What about chemical attractions?" he asked smoothly, looking her up and down with a raised eyebrow.

"Excuse me?" she asked, taken off guard.

"Chemical attraction: the force drawing atoms to each other and binding them together in a molecule," Chuck recited as if he were reading a definition straight out of a chemistry textbook.

"I understand what chemical attraction is, Bass," she said frustrated. "What I don't understand is what it has to do with anything."

"You said chemical reactions aren't instantaneous. They can take some time. Are chemical attractions instantaneous?" he asked leaning close to her, his golden brown eyes boring straight into her darker ones.

Her heart skipped a few beats. It always did when he looked at her with that intensity, but she managed to keep a cool exterior. "Yes," she answered calmly.

Chuck leaned back, moving away from her. "That's what I thought," he said, smirking. "You know, some would say that we have a chemical attraction."

Blair let out a less-than-ladylike snort. "Oh, please," she said, rolling her eyes.

"It's true. Like there's some undeniable force between us," he said, getting up from his stool and standing in front of Blair, whose back was to the table, and putting his hands on either side of her, blocking her in.

She looked at him through narrowed eyes. "There is a force between us, Bass, but it isn't attraction. It's called detestation," she said, contempt radiating in her voice.

Chuck leaned in ever closer. "That's kind of a strong word, don't you think?"

He was now way too close for her comfort. "No," she said, placing her hands on his chest and pushing him away with all the force she could muster.

He relented and settled himself back onto his own stool. She continued. "I think it's the perfect word. I loathe your very presence. In fact, I hate everything about you," she said, her voice rising with every statement.

"I hate those stupid little bowties you wear," she said, grabbing at the one he was wearing, and to her surprise, it was a clip-on, it came off in her hand. Tossing it aside, she continued her tirade. Now that she was starting, there was no stopping her.

"I hate that stupid scarf," she said, motioning to his "signature", lying abandoned on the floor with his bag. "I hate that stupid infamous smirk of yours. I hate the stupid way you tilt your head to the right when you're asking a question. I hate the stupid inflections in your voice when you're attempting to hit on someone."

Chuck, completely unfazed by her little rant, coolly smoothed his hair back with his hand. "You mean…this voice?" he asked amused, emphasizing the "this" with a low, seducing tone.

"Yes," she answered honestly. "And I especially hate that it works on me… every single freaking time," she admitted, while inwardly scolding herself for allowing his ego the satisfaction of knowing that he, indeed, held a certain power over her.

"I'm telling you…" Chuck said, running his hand through Blair's hair. "…chemical attraction."

Blair shook him off, trying to put aside her temporary of weakness. "No, a chemical attraction is sodium and chlorine. We are two metals: too much alike to form a bond."

"Did you know that one of the properties of metals is high lust?" he asked in the same tone she was referring to just a moment earlier, the insinuation clearly evident in his voice.

She decided to ignore the insinuation. "I believe you are thinking of luster," she corrected, avoiding his eyes.

Chuck, noticing her averting eyes, smiled to himself. He was getting to her and he damn well knew it. "They are also good conductors of electricity."

A blush immediately rose in Blair's cheeks. She had to collect herself for a moment before she allowed herself to meet his gaze. "Let it go, Bass," she said, forcing herself to sound calm and indifferent. "And now that I think about it…you are a noble gas: unable to form a bond with anything."

She looked back down, shuffling through her lab papers. "At least for more than a night," she muttered under her breath.

"Do I detect a hint of jealousy, Waldorf?" he asked, eyeing her cockily.

All the previous hints of Blair slowly giving into Chuck's advances quickly melted when she heard him utter that statement in the smuggest tone possible. "Not even close," she snapped, her eyes shooting up to look at him fiercely.

Chuck, however, seeing her reaction only added to his amusement. "A lot of jealousy?" he asked confidently.

Inside, Blair was fuming. She wanted to smack his smug little smirk right off his face. "Don't flatter yourself. Hand me that beaker with ice water so the crystals will form faster," she demanded, wanting to change the subject…quickly.

He slid the beaker, along with himself, toward her. "You know," he said now so close to her, she could feel the warmth of his breath on her face. "if I could rearrange the periodic table, I'd put Uranium and Iodine together."

Blair scooted her stool away from him, her eyebrows knitted together, genuinely confused by Chuck's sudden shift in conversation.

"Get it? U and I?" he asked when he received no response from her. "You know...you and me?" he said, trying again and emphasizing the pun by pointing between him and her.

She crossed her arms, clearly not amused. "If you have to explain the joke, chances are, it isn't very good."

Chuck's jaw dropped as he feigned offense. "It wasn't a joke. It was a chemistry-related pick-up line."

Blair raised an eyebrow in amusement. "Those exist?" she asked incredulously.

"Are you uranium? Because you're the bomb."

She scrunched up her nose at him. "What is it with you and uranium?" she asked seriously.

Chuck shrugged. "Don't know," he admitted casually. "But did it work?"

Blair shook her head causing her glossy curls to fly out around her. "Not even close."

He pursed his lips in thought. "Let me try again," he said, rolling up the sleeves of his shirt, getting down to business. "I have recently discovered a new element called Beautium and it looks like you are made of it."

She bit the inside of her lip. That one, as cheesy as it was, made her want to laugh. However, she resisted and simply looked at him, trying to seem unimpressed. "Try harder," she told him.

"I lost my atomic number. Can I have yours?"

"Now that's just sad."

"If I was an enzyme, I'd be DNA helicase so I could unzip your genes."

This time, a laugh escaped from Blair's lips before she could stop it. "That's biology, dumb-Bass," she said, shaking her head.

Chuck, ignoring her comment, looked at her victoriously. "It got you to laugh, didn't it?"

Taken aback, she thought about it for a moment. "Yeah, I guess it did," she admitted with a small laugh.

"Then mission accomplished," he said, staring at her shamelessly with that infamous smirk.

Flustered, Blair snapped out of it and attempted to refocus on the task at hand. "Look, we are never going to get this done if you just keep rattling off cheesy pick-up lines," she said, pulling the beaker toward her. "We have to purify the product by doing a recrystallization by-"

She was cut off, however, by Chuck slipping off his stool and in one fell swoop, pulled her off her own stool, took her in his arms, and pressed a hard kiss onto her lips.

When he pulled away, Blair could only look at him in complete shock. "What the hell are you doing?" she managed to squeak out, her heart beating wildly.

"Testing a hypothesis," he told her quickly before kissing her again.

That didn't quite clear up her confusion. "And just what, exactly, is the hypothesis of yours?" she asked.

"The rate of chemical attraction between us. And you know, they say you should do an experiment in triplicate to ensure the quality of results, so…" And with that, Chuck kissed her for a third time, this time longer and deeper and with Blair reciprocating the action.

When they pulled away, both were breathless. Chuck, however, broke the silence first. "Yup," he said with yet another smirk. "The tests are conclusive. Our rate of chemical attraction is off the charts, Waldorf. You can't deny science."

"Science, huh?" Blair asked, looking at him, her eyes dancing.

"That's right."

"I guess I really can't argue with science," she said, grinning, as she moved toward him to go for another kiss.

"Glad to hear," Chuck said, quickly pulling away and sliding back into his seat. Blair, who was taken off guard, remained rooted in her spot, gawking at him. Chuck however, smiled at her with a mischievous look in his eyes.

He patted the seat next to him, the one Blair was occupying earlier. "Now let's finish this thing up so we can go back to my limo and create some chemical reactions of our own," he said, his tone low and full of insinuations.

Blair, happy to oblige, sat back down and the pair worked quickly so they could get out of the school continue the experiment on their own terms.